Mobile terminals are used today by a significant number of people. In addition, with advances made in circuit design and battery life, the size and weight of mobile terminals has decreased over the lifetime of this product.
Because of the size and weight limitations, designers of such devices have difficulty including as many desired features in any one device. For example, with respect to a device for use as a cellular telephone, it is a challenge to include in that device any additional features that would enable the user to operate the device as something else, such as a personal digital assistant (PDA). This is due in part to the fact that a cellular telephone requires the use of a numeric keypad, while a PDA uses an alphanumeric keypad. To include both in one device requires miniaturization of parts and design. Thus there is a balance in providing as many advantageous features consumers want on a device, with the size and weight of the device so that it is not overly bulky or heavy. Often a compromise is made on the selection of some features in an effort to maintain a small, light weight design. Thus, the user is limited in the number of ways in which the device may be used.
Mobile terminals, such as cellular phones and personal digital assistants (PDAs), feature a variety of housing configurations. There are, for example, flip designs, “jack-knife” designs, and “candy bar” designs. Flip designs may include a flip portion mounted to an end of a housing with one or more hinges along the end of the housing. The operative faces of the flip and housing oppose each other when the flip is closed and are exposed when the flip is open. Jack-knife designs may include two housings, where one housing is rotatably mounted to the other housing with a pin-type connection made across the thickness of the housings, disposed at one end of the terminal when the housings are in the closed position. The operative face of one housing is always exposed, while the operative face of the other housing is hidden when the terminal is closed and is exposed when the terminal is open. Candy bar designs include a single housing, and are elongated, suggestive of a candy bar shape. However, with planar housings, the key pads are always exposed and may be activated accidentally. Also exposed keypads may wear out prematurely rendering the terminal unusable.
With respect to hinged and rotating designs, there is a challenge in ensuring that all the electrical contacts and power are provided throughout the housing to ensure effective operation of the device. For example, if the wiring does not have sufficient flexibility to move freely when the flip phone is flipped open, the wires will not allow the device to work properly or power may not be distributed to both sides of the terminal device and therefore render the device inoperative.
Many mobile terminals currently include full “qwerty” keypads, with numeric keys hidden within the keypad and accessible for use by depressing a function key first. Such a design reduces the number of keys required, but may make it difficult to identify and use the numeric keys. Most mobile terminals that include such keypads do so with the substantially planar, single housing design, and have the keypad and display on the same operative face of the housing. Incorporating a display and a keypad into the same face, however, results in a screen size substantially smaller than the face, possibly with keys too small to easily use with one's fingers. Many terminals with full keypads also do not have the form factor of a phone that users are accustomed to and may prefer.
It is a challenge to designers of mobile terminals to design a terminal that is of sufficient size to enable the user to operate the keys on the keypads effectively, yet make the device small enough so that it is easily mobile and may be carried in a pocket or handbag. In addition, because of the size limitations, there is a challenge to find sufficient space on the terminal body to provide the user with as many features as possible for the user to incorporate into the mobile device, while maintaining ease of portability. Also, where the terminal configurations are made of more than one part and move relative to each other. There is a further challenge to ensure that the wiring of the device is not compromised during movement and that current and power are properly distributed during operation of the device.